It is well known to add dyes and markers to liquid petroleum products as a means of identification for various purposes. For example, a fuel sold for agriculture purposes and taxed at a low rate may be tagged with a marker so that it can be identified if the fuel is illegally used in highway vehicles for which fuel is taxed at a higher rate. Markers may be used by a petroleum retailer to identify their brand at local filling stations.
While a large number of chemical compounds have been proposed as markers for petroleum fuels, in practice, the number of such dyes actually used is limited to a few accepted compounds. To be suitable as a petroleum fuel marker, a chemical compound must first of all be soluble and otherwise compatible with the petroleum fuel. Furthermore, there must be a way of identifying the presence of the marker in the tagged petroleum fuel, and for certain purposes, such as brand identification, this identification should be quantitative. Frequently, the method of identification involves extraction with an aqueous medium, e.g., either an acidic or alkaline medium, depending upon the marker, and often a chemical reaction which develops a color or a more intense color in the marker. It is desirable that a marker be silent, that is, while in the petroleum fuels at the tagging level, the marker should be colorless or substantially colorless, or else masked by natural colorants in the petroleum fuel or by other dyes added to the petroleum fuel. With the several rigid requirements for a good marker, the availability of commercially suitable markers remains limited.
While the use of markers has been most explored in respect to petroleum fuels, the use of such markers is expanding into other areas as well. For example, manufacturers of asphalt additives or concrete additives may wish to tag their product so that it can be determined if their additive in the recommended amounts was, indeed, added to a product in the correct amounts.
The present invention is directed to the use of polymerizable markers as a means of tagging and identifying materials, particularly liquid materials.